The present application relates generally to energy-reversible compositions containing drugs or other molecules. In particular, the present application relates to drug moieties and other biologically active moieties, herein denoted xe2x80x94X1A, bonded to a cinnamic acid or related molecular core (herein denoted Zxe2x80x94CINN).
In prodrugs, an active drug is typically bonded to another molecule to alter the drug""s properties in a reversible manner and regulate the drug""s release. The majority of prodrugs have an ester or amide bond formed between a hydroxyl, amino, or thiol group of a drug moiety and the carboxylate group of a carrier molecule, or vice versa. Depending on the chemical properties of the molecules making up the linkage, these prodrugs have hydrolysis rates that range from minutes to days. Temperature, pH and the chemical composition of the solution in which the prodrug is administered can also influence the rate of release of the active ingredient from the prodrug. The very short hydrolysis rates and very long ones are generally not useful. Hydrolysis rates in the range of 0.5-48 hours are generally more desirable. Prodrugs can be designed 1) to change aqueous solubility properties of the drug, 2) to change circulating lifetime of the drug, 3) to be more lipophilic than the parent compound, allowing greater penetration of biological membranes and therefore greater access to diseased sites, 4) to have lower toxicity, for example, by allowing the prodrug to be transported to its site of action in its inactive form, where the inactive prodrug is converted to the active parent compound at its target site, 5) to bind selectively at a target site, because of a specific targeting molecule attached to the prodrug complex, or for other purposes.
Over the years, a large number of prodrugs have been developed. For example, some have suggested preparing amino acid esters of various therapeutic agents. Others have suggested forming polymeric conjugates with ester linkages. In either case, the active compound is released in vivo via hydrolysis. Another approach is described in U.S. Pat. No. 6,071,908 which discloses a method of treating neoplastic disease using a radiation-activated cytotoxin prodrug. The prodrug releases a tumoricidal cytotoxic effector using reducing agents generated by the radiolysis of water.
A still further prodrug approach relies upon the use of light for reversible control of enzyme activity, (see U.S. Pat. Nos. 5,114,851 and 5,218,137 to Porter et al.). Specifically, Porter et al. disclose coupling an enzyme active site amino acid residue to cinnamate (CINN) derivatives to form o-hydroxy cinnamate substituted esters or acyl enzymes, which are inactive. On photolysis, the bond with the active site amino acid residue is cleaved and the active site is exposed. There are a number of potential advantages associated with this concept. In theory, using this technique, the artisan has the ability to control in vivo enzyme activity specifically and rapidly, by exposure to light in vivo or ex vivo.
In spite of the advances of Porter et al., work in this area has continued. There continues to be a need in the art to expand the cinnamate core platform beyond inhibited enzymes. It would also be desirable to provide a means for better targeting non-enzyme therapeutic compounds to sites of interest in the body. In the past, the artisan has had little ability to control when and in what amount a drug can be generated in the therapeutically desired area. Moreover, the ability to reduce the amount of administered drug and/or peripheral organ damage caused by untargeted delivery would be welcomed by those in the art. It would also be advantageous to have the capability to independently initiate or control the hydrolysis of a prodrug. It would also be advantageous to have a means to localize a prodrug or other conjugate to a diseased area. The present invention addresses these and other needs.
It is an object of the present invention to provide improved compositions designated herein as Zxe2x80x94CINNxe2x80x94X1xe2x80x94A, that can controllably release the xe2x80x94X1A portion thereof at a controlled rate, whether by hydrolysis or by energy input such as light or ultrasound.
It is another object of the present invention to provide means to facilitate the targeting, delivery and binding of a composition containing Zxe2x80x94CINNxe2x80x94X1A to a surface or a diseased site, by incorporation of additional molecule(s) attached to Zxe2x80x94CINN, denoted B-L, which are capable of binding to that site, to concentrate the conjugate prior to release of xe2x80x94X1A.
It is another object of the present invention to provide an additional site on Zxe2x80x94CINNxe2x80x94X1xe2x80x94A compounds which can be derivatized in various ways, including with groups designated herein as xe2x80x9cB-Lxe2x80x9d, to provide compositions designated herein as B-L-Zxe2x80x94CINNxe2x80x94X1xe2x80x94A, which have additional properties, such as stability, increased circulation time, targeting capacity, or immobilization to appropriate supports.
It is therefore an object of the present invention to provide a prodrug composition, and the method of preparation thereof, which releases an effective drug at a controlled rate by application of an exogenous stimulus.
It is another object of the present invention to provide means to facilitate the delivery of a prodrug composition to a diseased site by incorporation of a targeting molecule.
It is another object of the present invention to provide means to alter a prodrug composition by incorporation of a molecule(s) to increase circulation time, solubility, or stability.
It is another object of the present invention to provide means to alter a prodrug composition by incorporation of a molecule(s) which can bind to a biological or non-biological surface such as a bead, stent, or other matrix material for purposes of slow release, purification of additional molecules, and the like.
It is another object of the present invention to bind and release biologically active molecules, other than enzymes, in the manner specified above.
These and other objects are provided by the present invention, which in one embodiment provides compounds corresponding to Zxe2x80x94CINNxe2x80x94X1xe2x80x94A and the formula: 
Formula I
wherein:
X1A is a residue of a releasable biologically active moiety;
R1 and R2 are individually selected from the group consisting of H, CH3, C2-C10 alkyls, C2-C10 alkenyls or C2-C10 alkynyls, each of which can be substituted or unsubstituted; straight or branched, C2-C10 heteroalkyls, C2-C10 heteroalkenyls or C2-C10 to heteroalkynyls and xe2x80x94(CR15R16)pxe2x80x94D;
wherein: R15 and R16 are individually selected from the group consisting of H, CH3, C2-C10 alkyls, C2-C10 alkenyls or C2-C10 alkynyls, each of which can be substituted or unsubstituted; straight or branched; and
C2-C10 heteroalkyls, C2-C10 heteroalkenyls or C2-C10 heteroalkynyls;
p is a positive integer from 1 to about 12;
D is selected from among xe2x80x94SH, xe2x80x94OH, X2, xe2x80x94CN, xe2x80x94OR19, NHR20, 
wherein:
R17 is H, CH3 or X3;
R18 is H, a C1-C4 alkyl or benzyl;
R19 is H, a C1-4 alkyl, X2 or benzyl;
R20 is H, C1-10 alkyls or xe2x80x94C(O)R21,
xe2x80x83wherein R21 is H, a C1-4 alkyl or alkoxy, t-butoxy or benzyloxy;
X2 and X3 are independently selected halogens;
R3 is H, CH3, or xe2x80x94C(xe2x95x90O)(CR15R16)wxe2x80x94D, where w is 0 or an integer from 1 to about 12, and D is H or as described for R1 and R2 
J is O, NH or S;
R4, R5, and R6 are independently selected from the group consisting of H, CH3, C2-C10 alkyls, C2-C10 alkenyls or C2-C10 alkynyls, each of which can be substituted or unsubstituted; straight or branched; C2-C10 heteroalkyls, heteroalkenyls or heteroalkynyls and halogens;
Z is H, NR7R8 or 
wherein R7 is selected from among H, CH3, C2-C10 alkyls, alkenyls or alkynyls which can be substituted or unsubstituted; straight or branched; C2-C10 heteroalkyls, heteroalkenyls or heteroalkynyls, or xe2x80x94(CR23R24)qxe2x80x94aryl, or R8,
wherein R23 and R24 are independently selected from the group consisting of H and C1-C10 alkyls;
q is an integer from 1 to about 6;
R8 is selected from the group consisting of (CR9R10)nxe2x80x94NR22xe2x80x94R11, (CR9R10)nxe2x80x94CH2xe2x80x94NHC(O)R26 and (CR9R10)nxe2x80x94CH2xe2x80x94E;
wherein R9 and R10 are independently selected from the group consisting of H, CH3, C2-C10 alkyls, C2-C10 alkenyls or C2-C10 alkynyls, each of which can be substituted or unsubstituted; straight or branched; C2-C10 heteroalkyls, C2-C10 heteroalkenyls or C2-C10 heteroalkynyls and halogens;
R26 is H, CH3, O-t-butyl, O-benzyl;
E is OH, SH or Oxe2x80x94C(O)R27,
wherein R27 is a C1-C6 alkyl, benzyl or phenyl;
R22 is H or CH3;
n is a positive integer from 1 to about 10;
R11 is H or -L-B,
wherein L is a linker; and
B is a second active moiety, reactive group moiety or a polymer; and
R25 is H, xe2x80x94C(O)xe2x80x94R28 or xe2x80x94C(O)xe2x80x94Oxe2x80x94R29,
wherein R28 is a C1-C6 alkyl or benzyl; and R29 is CH3, t-butyl or benzyl.
Pharmaceutically acceptable salts, including Clxe2x88x92, Brxe2x88x92, HSO4xe2x88x92, etc., are also provided.
In some preferred aspects, X1A is a residue of a biologically active molecule such as paclitaxel or another chemotherapeutic agent (drug) which bonds to Zxe2x80x94CINN as a prodrug.
In still further aspects of the invention, Zxe2x80x94CINNxe2x80x94X1A compositions are derivatized utilizing the reactive Z site of Formula I. In particular, when R8 is (CR9R10)xe2x80x94NR22xe2x80x94R11, and R11 is L-B, the artisan is provided with light activatable prodrugs which are linked to, among other things, targeting antibodies or polymers such as PEG or other polymers. The moiety xe2x80x9cBxe2x80x9d can be xe2x80x94H, or a natural polymer, such as DNA, a synthetic polymer, such as PEG, synthetic or naturally occurring organic molecule, or natural or synthetic targeting peptide, polypeptide or protein such as a monoclonal antibody (mAb).
In other aspects of the invention, Hxe2x80x94X1A is a biologically active molecule or moiety such as a protein whose side-chain xe2x80x94O, xe2x80x94S or xe2x80x94NH corresponds to X1 of Formula (I) which is bonded to the C(xe2x95x90O) of the Zxe2x80x94CINN. Thus, Hxe2x80x94X1A is a drug, etc. rendered inactive through its bond to Zxe2x80x94CINN and is preferably capable of having its biological activity restored by one or more of hydrolysis, exposure to light or other energy source after targeting has been allowed to proceed in vivo.
As a result of the present invention, several advantages are provided. For example, these Zxe2x80x94CINNxe2x80x94X1xe2x80x94A inactivated compositions can have various beneficial properties, such as increased targeting ability, solubility, increased half-life in circulation, or other features. In addition, L-Zxe2x80x94CINNxe2x80x94X1xe2x80x94A inactivated compositions can be immobilized by crosslinking to support materials via the linker L. The support materials can be any industrially or pharmaceutically suitable materials such as organic polymers, inorganic polymers, natural polymers, biopolymers or zeolites and can be in the form of films, membranes, filters, beads, particles, resins, microparticles, or columns. Alternatively, B-L-Zxe2x80x94CINNxe2x80x94X1xe2x80x94A can be attached to supports by mechanisms such as affinity or by additional coupling reactions with activated support materials.
The composition of Formula I, B-L-Zxe2x80x94CINN-X1A, can be used with a pharmaceutically acceptable carrier for administration to a patient. In one embodiment, the carrier is one of liposomes, microcapsules, enteric coated formulations, and formulations for pulmonary (inhalation) administration.
The acyl bond connecting Zxe2x80x94CINN and xe2x80x94X1A is susceptible to hydrolysis and/or energy activation. Absent energy activation, the acyl bond can be relatively stable at a approximately neutral pH is the dark. Upon energy activation, the acyl bond is rapidly hydrolyzed to release biologically active HX1A. In one embodiment, HX1A is released following exposure to a source of radiation such as visible light, infrared light, ultraviolet light, ultrasound, microwave, and radiation. In anther embodiment, the energy source is radiation generated by a radioactive material such as U*, Co*, Fe*, I*, Cs* or Tc* (M* denotes a radioactive material). In a preferred embodiment, the energy source is light with a wavelength in the range from 300 to 850 nm. In one specifically preferred embodiment, the light has a wavelength in the range from 300 nm to 450 nm. The most preferred light has a wavelength in the range from 350 nm to 420 nm.
In further aspects of the invention, methods of preparing and using the compositions of the present invention are also provided.